1. Field of the Invention
This invention relates to edgers with a powered cutting assembly that is used to define a demarcation, as between different landscape areas.
2. Background Art
Over the years, the landscaping industry has become more meticulous in terms of making a precise transition between different landscape areas. For example, where lawns are adjacent to beds with flowers and/or bushes, and/or surround trees, a distinct and precise dividing line is desirably formed. Commonly, this line is defined by cutting a trench with a vertical wall at the edge of the lawn area. This avoids spreading of the grass to the adjacent beds and also produces an aesthetically pleasing, sharp, dividing line between the different types of landscape.
It has long been known to form such trenches utilizing conventional hand tools, such as flat-bladed shovels. While manual formation of trenches is desirable from the standpoint of the flexibility and control that it affords a worker, this process has a number of drawbacks.
First of all, manual trench formation can be labor intensive. Since the trench is formed several inches at a time, extended trench formation may require an investment of many man hours, which could dictate the need for potentially large crews. This task is potentially made even more onerous by dry and hard ground conditions. Even with large crews, the nature of this work is such that it may lead to significant worker fatigue.
Another problem with manual trench formation is that it does not lend itself to precise trench placement. Since the trench is formed progressively in small increments, there may result an overall jagged appearance that does not precisely follow an intended course.
Still further, workers must deal with the material removed during the trench formation. In the typical formation using a shovel, large chunks of terrain may be separated. These chunks must either be hauled away to another site or broken up to be distributed in the beds so that they are not identifiable.
Edgers with powered cutting assemblies have long been used in the landscaping industry. One such edger has a rotary, generally flat, disk-shaped blade that is caused to penetrate the ground to produce a trench with spaced vertical walls. The edger has a frame with one or more wheels that facilitate controlled repositioning thereof over a subjacent surface. While this type of edger is relatively simple to use and overcomes problems associated with manual trenching, edging using such a structure has its own limitations and drawbacks.
First of all, the cutting blade is efficient only when it is operating in a state wherein it can aggressively cut the underlying terrain. After extended use, such a blade may be prone to wear, and even failure. In forming a trench in different locations, or over an extended length at a single location, the blade may encounter roots, rocks, metal objects, and virtually an unlimited number of different immersed objects that are hard enough to progressively wear or damage teeth on the blade. Even without encountering any foreign objects, the blade may be compromised due to the continuous abrasive effect from the ground composition, be it dirt, sand, or the like.
A further drawback with this type of edger is that effective trench formation may require a complementary manual step after the cutting blade has performed its intended operation. That is, once the two vertical walls are formed, the material defining one of the vertical walls must be removed. This step is required to create a step below the height of the vertical wall, as at the lawn, whereby a space is defined to accept mulch, or the like, that can be filled to the height of the lawn. This step also avoids the collapse of material into the trench that is likely to otherwise occur naturally under normal weather conditions, or in the event that there is pressure applied in the vicinity of the trench, as by normal traffic or the passage of equipment. The end result is that manual labor is required, with the same associated drawbacks as discussed above.
It is known to produce a beveled trench with an edger that utilizes a rotary cutting assembly. One known construction has a frame with a series of teeth that are strategically disposed so that they cooperatively produce a beveled or “V”-shaped trench as the cutting assembly is directed into underlying terrain and rotated in operation. This design is preferred from the standpoint that it makes possible the elimination of heavy manual steps and causes a trench of desired configuration to be formed in a single pass of the edger over the underlying terrain. Commonly, this type of edger is supported on a wheeled frame and is steered and advanced through frame components that can be engaged by an operator with the operator in a comfortable, upright position. However, this design has also had significant drawbacks which have limited its viability and acceptance in the industry.
First of all, the teeth are commonly made with an elongate configuration and are oriented on a support so that a substantial length of each of the teeth engages the underlying terrain to produce the cutting action. During operation, there may be significant bending forces imparted to the teeth that dictates that there be an overall heavy construction, that may nonetheless be prone to failure. Additionally, the repetitive contact of a large area of the teeth makes the teeth prone to progressive abrasion that over time may not only affect cutting ability but may alter their shape and that of the cut effected therewith in the terrain.
As a result, these cutting assemblies may have to be made with such a robust construction that they are impractical from both the standpoint of weight and cost. Even then, the above construction makes the teeth unavoidably prone to dulling, reconfiguration, and potentially failure.
These altered teeth conditions could lead to some other significant undesired consequences. Most significantly, if the teeth do not aggressively cut the underlying terrain, there may be a tendency of the edger to “jump” randomly from the terrain in operation. Aside from the fact that the result is an imprecise trench formation, this condition may lead to an injury.
Alternatively, a worker contends with the fact that the resulting trench may be imprecisely formed. This leaves the option of leaving the trench in this condition, which may be aesthetically compromised, or manually dressing the trench, which introduces other inconveniences and costs, as discussed above.
Alternatively, the user of such edgers may be required to sharpen or periodically refurbish the cutting assembly. This leads to down time and may be impractically expensive.
Still another problem associated with the latter type of edger is their propensity to accumulate dislodged material in a manner whereby the same interferes with the edger operation. As one example, a cutting assembly may have a wall that moves in close proximity to a main frame and/or a component thereon, such as a guard. In moist terrain, as cutting takes place, material may accumulate between the cutting blade assembly and adjacent components relative to which the cutting assembly moves. The accumulation may be to the point that there is a constant frictional force produced upon the cutting assembly, as an incident of which there may be abrasive wear. Even if there is not significant wear, the foreign material buildup may result in there being undesired, extra loading upon the drive for the cutting assembly. Still further, this buildup may be to such an extent that it blocks the normal anticipated path of movement of the terrain as it is being broken up and redistributed in operation.
An additional problem with this conventional powered edging structure is that there is also a tendency of existing designs to keep the cut terrain in place in the trench. This potentially results in a churning action as the cutting assembly continues to rotate within the accumulation of cut material that may be in large proportion stagnant within the completed trench. This phenomenon also contributes to buildup of foreign matter on the cutter assembly and elsewhere throughout the edger. These conditions all detract from the efficient and effective operation of the edger.
In spite of the desirability of using edgers that are powered, landscapers continue to manually form beveled trenches, and contend with the inherent difficulties. The industry continues to seek out designs that make powered edgers more practically usable, particularly from the standpoints of efficiency, effectiveness, weight, reliability and affordability.